U.S. Pat. No. 5,507,501 (Palmer) and 6,575,475 (Duncan) both disclose apparatus used in testing plumbing installations for leaks that use sealing discs which are weakened by grooves. When testing is completed, a lug secured to the sealing disc is grasped and a force exerted to tear the sealing disc along the grooves. The Palmer reference teaches securing such a sealing disc in place using a wax seal or glue. The Duncan reference incorporates such a sealing disc into a pipe coupling.